Patent GB-442128-A (GB)
Title: Preselecting mechanism for change speed gearing
IPC: F16H63/36
Filed: 1934-05-01
Abstract: 442,128. Controlling change speed gearing. SERVO-FREIN DEWANDRE SOC. ANON., 68, Quai de Rome, and VINCENT, C., 61, Rue Jos. Deflandre, Sauheid Chenee, both in Liege, Belgium. May 1, 1934, No. 13162. Convention date, March 12. [Class 80 (ii)] [See also Group XXXII] Electro - pneumatic mechanism, for preselectively controlling change-speed selector rods on a vehicle, comprises fluid-pressure motors, energized one at a time by electromagnetic valves under the control of electrical circuits prepared by the motors themselves and by a manual preselector-switch. The change is rendered effective by closing a switch operated by the main clutch, which latter may be automatic under control of the accelerator pedal, acting through a vacuum motor. Two forms are described, one, Figs. 1, 3, 13 and 14, in which two separate double-acting motors 37 each act directly on a selector-rod 12 or 12a through a lever 19 or 19a, pivoting with a rockshaft 18 or 18a ; and a second form, Figs. 18-20, in which all longitudinal striking movements are effected by a single double-acting motor 38, whilst transverse selecting movements are performed by a doubleacting motor 38a, which shifts a single gateguided lever 19 into selective connection with any of three selector-rods 69, 70, 71, whilst the lever remains in operative connection with a transverse slot carried by the piston-rod of the striker-motor 38, which latter is biassed towards neutral by a spring 48. The control mechanism for the first form is shown in Figs. 13 and 14, the circuits of the four electromagnetic valves 87, 88, 89 and 90, which control the supply of engine-suction to the two double-acting motors 38, being completed through a manual preselector-switch 76, an executive switch 79, closed by the main clutch-pedal 80, and motoroperated switch-gear, operating somewhat in the manner of an electrical interlock. The latter comprises pairs of spaced contactbrushes 72a, band 73a, b, carried respectively by the motor-operated rockshafts 18, 18a, Figs. 1 and 13, and wiping over fixed contacts 74a ... c and 75a ... d in such a way that the current for either of the two valves of one selector-rod is derived through the switch 72 or 73 of the other selector-rod and only when the latter has reached its neutral position. Hence a change involving a transfer from one rod to the other, i.e. between first and second speeds, takes place in steps, the appropriate motors being energized only one at a time. During such a change, the first rod is neutralized by a combination of fluid-pressure and a spring 48, Fig. 1 (or Fig. 18), the said spring acting in both directions on the piston-rod 34, through looselymounted abutments 43, 44, engaging shoulders on the rod and constituting the operative pistons of a dashpot retarding device comprising a liquid-reservoir 52 and a throttling-orifice 51, adjusted by a screw-down needle-valve. Complete neutralizing of the gear at any time can be effected by the springs, simply by depressing the clutch-pedal to unlock the levers 19, 19a. Fig. 6 shows a dashpot which damps engaging movements only, the return neutralizing movements being freed by means of loose flap-valves 59, pressed against apertured pistons 44 by a light spring 60, and a pair of throttling apertures 53, 53a giving a progressive action. The gearstriking levers 19, 19a are normally locked in gear and neutral positions by a pivotal locking- member 25, which during a change, is moved out of engagement with notches 24 in, or the endfaces of, the levers 19, 19a by depression of the main-clutch pedal, with which latter the locking- member 25 is mechanically connected. In Figs. 18-20 the transverse selecting-motor 38a is biassed by a double-acting spring 48a into the central position for engagement with the selector rod 70, and it also operates a contactbrush 72a, which, together with a throw-over switch-arm 101, operated by the striker-motor 38, take part in the preparation of the valve circuits. The striker-motor valves 89, 90, derive their current from the main battery-lead 79c, which is directed through the contact-brush 72a of the selector-motor 38a to three fixed contacts 76b, c, d, connected selectively through a contact-plate 104 on the preselector-switch 76, with contacts R, 1 ... 5, leading alternately to the striker-motor valves 89, 90. By this arrangement the selected striker-motor is only energized when the selector-motor '38a has moved the shifter-lever 19, Figs. 18 and 19, through the gate 109, into engagement with the desired selector-rod 69 ... 71. The valves 87, 88 of the transverse selector-motor 38a receive their current directly from the main lead 79c, through lead 91, contact-plate 76a, preselector contact-plate 105 and contacts 106a, b, 107a, b, four only being required since the selector motor is not energized in the central position for second and third speeds. The preselectorswitch 76 also controls three spring-loaded switches 96, 97, 98 which connect the throwover switch arm 101 respectively with the three contacts 92, 93, 94 of the switch 72a of the selector-motor 38a. The purpose of the switches 96 ... 98 is to energize the strikermotor 38 and neutralize the gear in a change involving transfer from one selector-rod to another. The throw-over lever 101, directly operated by the striking-motor, ensures that the appropriate neutralizing valve 89 or 90 will be operated and also breaks the circuit when the neutral position is reached. If the change does not involve transfer from one selector-rod to another, i.e. from fourth to fifth speeds, the switch, say 98, appropriate to the operated selector-rod is broken by the preselector switch 76 and this neutralizing circuit is inoperative. A spring 48 again assists the striking-motor 38 in the neutralizing operation. The selectorrods 69 ... 71 are locked in gear and neutral positions by a clutch-released bolt 27. A mechanical interlock for the rods comprises a cage 66, Fig. 9, and two drift-blocks 67, 68. U.S.A. Specification 1,911,599 is referred to.